Synchronizing device

ABSTRACT

The invention relates to an indexing gear (21) for a synchronizing device (1) for a geared speed change transmission installed in motor vehicles to which a coupling body (22) as well as a friction ring (23) are allocated. In accordance with the invention, the indexing gear (21), the coupling body (22) as well as the friction ring (23) are constructed as component parts which can be prefabricated, which are joined in a rotatably fixed manner.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.09/067,518, filed Apr. 28, 1998, now U.S. Pat. No. 6,016,895.

BACKGROUND OF THE INVENTION

The invention concerns an indexing gear for a synchronizing device of ageared speed change transmission installed in motor vehicles to which acoupling body as well as a friction ring is allocated, whereby thecoupling body is connected form-locking with a sliding connector to anexternal gearing during a shifting process, and a conical friction areaof the friction ring (23, 33) interacts with a synchronizing ring duringsynchronization.

Synchronizing devices of the above-mentioned type find application intransmission gears in order to simplify shifting gears of a manuallyshiftable gear box. A representative synchronizing device is known fromDE 37 29818 C2. This document discloses a synchronizing device on theindexing gears, which are also known as sliding gears, of which first ofall an axially oriented coupling body is connected to which a frictionring is introduced. Due to their customary one-piece construction, allsegments of this subassembly are made of one material. Owing to thedifferent functions or modes of operation of individual areas of thesynchronizing unit, hardening of the gearing of the indexing gear andthe external gearing of the coupling element, for example, is necessary,as well as polishing the friction area of the friction ring. To limitthe hardened zones, which are restricted to the gearing, a greatexpenditure is necessary to avoid an unwanted further hardening on allother areas of the of the indexing gear. It is the same with thegrinding of the friction area of the friction ring, as the complexconstruction of the indexing gear prevents a rapid clamping as well aschanging this component part.

An indexing gear is provided by the present invention, the constructionof which assures a simplification of individual elements and reducesprocessing and hardening costs in comparison with the state of the art.

SUMMARY OF THE INVENTION

The previously defined object is accomplished in accordance with theinvention by the features specified in the claims.

In accordance with the invention, several, in each case individuallyprefabricated construction units are allocated to the indexing gear orsliding gear which are joined together in a rotationally fixed manner tocreate a unit. This unit includes a coupling body and a friction ring inaddition to the indexing gear. Here the indexing gear and the couplingbody are inseparably connected with each other. The friction ring is atthe same time joined and aligned in a rotationally fixed manner on theunit to ensure an inseparable connection. Between the indexing gear andthe coupling body, preferably a weld or an adhesive can be inserted. Thereconfiguration of the indexing gear in accordance with the inventionmakes possible an individual processing or heat treatment, keeping withrequirements and adapted to the respective stresses of the individualconstruction units, owing to which exerting an influence on adjacentareas of the synchronizing unit is prevented. The gearings of thecoupling body as well as of the indexing wheel are, in keeping withrequirements, hardened corresponding to the respective standards,without influencing other component parts of the synchronizing unit.Constructing the component parts in accordance with inventionfurthermore enables a simplification, that is a manufacturing-optimizedconstruction of the individual construction units, especially of theindexing gear, which contributes to a reduction in cost.

Other advantageous configurations of the invention are recited in thedependent claims, which are explained below.

In accordance with a preferred configuration of the invention, variousmanufacturing processes can be used to produce the subassemblies of theinvention. For the indexing gear, this may be constructed as a castpart. Alternatively, the invention likewise includes an indexing gearconstructed as a powder metal part. The disk-like constructed couplingelement is by way of contrast designed in accordance with the inventionas a high quality stamped metal part. For subassemblies of this design,a high quality stamping represents a cost-optimized manufacturingprocedure with which at the same time the construction unit can bemanufactured with an exactitude which requires no repair. A preferablynon-cutting, drawing method is suited for manufacturing the sheath-likeconstructed friction ring. This procedure enables manufacturing afriction ring optimized as to weight associated with a sufficientinherent stability of the friction ring while at the same time meetinghardness standards.

The invention moreover includes the individual elements of thesubassembly being manufactured of various materials or raw materials. Ahigh quality casting GS 45 is preferably suited for the indexing gear, C15; CK 15 for the coupling body and for the friction ring, 100 Cr6; 16MnCr5; C 80 M or even coating this material.

In one configuration of the invention, the indexing gear is provided onone side with an axially projecting rim on which the coupling body aswell as the transmission element are centerable. The coupling body andfriction ring are then centered on the rim and axially seated against ashoulder of the indexing gear. When using an indexing gear provided as ahigh quality casting with a high finish quality, a mechanical reworkingof the axially projecting rim is unnecessary, which leads to a furthercost reduction.

The subassembly of the invention moreover includes an integralconstruction in connection with which the friction ring and the couplingbody are constructed in one piece preferably in the form of an L-shapedprofile. An axially projecting rim on the indexing gear itself can atthe same time likewise be used to accommodate this one piececonstruction.

The invention likewise includes an assembly whose disk-like couplingbody is centered over an internal diameter on the rim of the indexingwheel, and the conically shaped friction ring is joined form-lockingwith the coupling body. For this, the friction ring has axiallyprojecting pegs on the side with the largest diameter area which engageform-locking into corresponding recesses of the coupling body. To createa rotation-fixed connection, stamping over the pegs in the area of therecesses on the coupling body presents itself, whereby a certain degreeof freedom remains for the friction ring for tolerance-conditionedalignment with the construction units which stand in operativeconnection with the friction ring.

For realizing a durable securing of the individual construction units ofthe subassembly, these are joined form-locking and inseparably with oneanother. In addition to welding and soldering, gluing can likewise beused. Furthermore, individual construction units can be permanentlysecured by a press fitting.

In a further advantageous configuration of the invention, thesubassembly of the invention is further provided with a synchronizingring. This way a simple synchronization is realizable in connection withwhich a synchronizing ring is guided on the friction ring or thefriction ring encloses the synchronizing ring. The subassemblysupplemented with the synchronizing ring represents a preassembled unitwhich, for example, includes all assemblies of a manufacturer which aredelivered to a vehicle manufacturer as supplier element. Theconstruction of the subassembly here enables an exchange from a simpleto a multiple synchronization. This way, the invention makes possiblethe use of a basic subassembly which, depending upon the synchronousoutput requirement, can be equipped with a varying number ofsynchronizing rings without altering the construction.

To produce a twofold synchronization, two synchronizing rings, which arearranged on both sides of the friction ring, can be allocated to thesubassembly of the invention.

The invention moreover includes a subassembly which is designed toprovide a threefold synchronization. For this, the indexing gear isprovided with an axially projecting inner cone which is arranged at adistance from the friction ring. A first synchronizing ring is installedin the compartment radially defined between the friction ring and theinner cone which is run on the friction areas of the inner cone and thefriction ring. The exterior of the friction ring forms a third frictionarea on which a second synchronizing ring is conveyed. As an alternativeto an internal cone joined in one piece with the indexing gear, aninternal ring can be inserted form-locking on the indexing gear can alsobe provided in accordance with the invention. For this, an inner conewhich is provided with parallel protruding pegs which engage inappropriate recesses especially offers itself.

The invention is represented in embodiments which are discussed in moredetail below.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe invention, will be better understood when read in conjunction withthe appended drawings. For the purpose of illustrating the invention,there are shown in the drawings embodiments which are presentlypreferred. It should be understood, however, that the invention is notlimited to the precise arrangements and instrumentalities shown. In thedrawings:

FIG. 1, a subassembly of the invention whose three individual elementsare represented at a distance to one another;

FIG. 2, a completed subassembly consisting of the three component partsdepicted in FIG. 2;

FIG. 3, the structure of a synchronizing device which has indexingwheels of the previous design;

FIG. 4, a further construction of a subassembly of the invention theparts of which are represented apart;

FIG. 5, a subassembly consisting of the component parts in accordancewith FIG. 4 in longitudinal section;

FIG. 6, a subassembly consisting of two component parts;

FIG. 7, a subassembly which is provided with a synchronizing ring passedon the friction ring for producing a simple synchronization;

FIG. 8, the combination of an indexing wheel of the invention withsynchronizing rings passed on both sides of the friction ring;

FIG. 9, a threefold synchronization in connection with which theindexing wheel is provided with an axially projecting inner cone in onepiece on which a first synchronous ring is run, and a second synchronousring is arranged on the friction ring;

FIG. 10, a threefold synchronization corresponding to FIG. 9 to thegreatest extent, with which, as distinct from FIG. 9, the inner cone isinstalled insertable in the indexing wheel.

DETAILED DESCRIPTION OF THE INVENTION

Certain terminology is used in the description for convenience only andis not limiting. The word "right," "left," "lower" and "upper" designatedirections in the drawings to which reference is made. The words"inwardly" and "outwardly" refer to directions toward and away from,respectively, the geometric center of the synchronizing device anddesignated parts thereof. The terminology includes the wordsspecifically mentioned above, derivatives thereof and words of similarimport.

A first embodiment of a subassembly 20 of the invention is shown in FIG.1 in which all component parts are represented apart. The subassembly 20includes an indexing gear 21, a coupling body 22 as well as a frictionring 23. This multipart construction of the subassembly 20 makes aselection of materials possible which is adapted to the respective needsor standards of the individual parts. At the same time, divergentprocedures for manufacturing these component parts can be used owing tothe different geometrical configurations of the individually constructedparts.

The completed subassembly 20 is depicted in FIG. 2, and include theindexing gear 21, the coupling body 22 and the friction ring 23, whichhas a conical friction area 28. For form-locking assembly of theseparts, the indexing gear 21 is provided with an axially projecting rim24 as well as with a shoulder 25 on which the coupling body 22 iscentered, and experiences an axial limit as it seats against theshoulder. In the area of an internal diameter of the coupling body 22,several notches 26 are provided which are distributed on the peripheryinto which the axially projecting pegs 27 of the friction ring 23 areinserted, whereby the pegs 27 are at the same time centered on the rim24 of the indexing gear. To ensure an inseparable connection of allconstruction parts of the subassembly 20, these parts are preferablywelded in the area of the rim 24. The friction ring 23 is furthermoreprovided with torsion protection 29 which is arranged running axially ona face turned away from the pegs 27.

The structure of a synchronizing device 1 can be understood from FIG. 3,which is illustrated in a longitudinal section. The structure includestwo subassemblies 3a, 3b of the previous one part design which arearranged apart on a gear shaft 2 rotatable by a gear 4. Each subassembly3a, 3b is provided with an indexing gear 5a, 5b having an externalgearing. Pointing in the direction of the gear 4, a coupling body 6a, 6bis in each case placed in front of the indexing gear 5a, 5b to which afriction ring 7a, 7b is connected. To distinguish the individualelements of the subassembly 3a, 3b, these are crosshatched differently.A synchronizing ring 9a, 9b is in each case conveyed on a conicallyrunning friction area 8a, 8b of the friction ring 7a, 7b whoseunilaterally bent section has a top gearing outside, which interactswith an axially movable sliding connector 10. The sliding connector 10is shaped like a ring element and includes the coupling support 4, andis joined with this by a gearing. The gearing profile of the slidingconnector 10 is complementary to the top gearings of the synchronizingrings 9a, 9b as well as of the coupling bodies 6a, 6b. An axialdisplacement of the sliding connector 10 in the direction of asynchronizing unit 3a, 3b up to a radial coverage of a coupling body 6a,6b, in connection with which this is joined with the sliding connector10 form-locking by the gearing, makes possible a transmission of forcefrom the gear shaft 2 to an indexing gear 5a, 5b, which in each casestands in engagement with a gear not further depicted in FIG. 1. A shiftfinger 12 which engages form-locking in a recess 13 of the slidingconnector serves to move the sliding connector. The shift finger 12 ispositionally stabilized on a control shaft 11 arranged parallel to thegear shaft 2 and for example, is movable in one of the axial directionsindicated by arrows by a control lever which can be activated manually.

A one part subassembly 3a, 3b in accordance with FIG. 3 would require ahigh cost manufacturing outlay, especially for hardening the gearing 14of the indexing gear 5b and the top gearing 15 of the coupling body 6b.An increased expenditure is likewise required for polishing the frictionarea 8b in connection with a subassembly 3b, if it is constructed as onepart owing to a more expensive clamping.

The structure of a second subassembly 30 in accordance with the presentinvention is shown in FIGS. 4 and 5. The subassembly 30 likewise hasthree component parts, the indexing gear 31, the coupling body 32 aswell as the friction ring 33. A difference from subassembly 20 (see FIG.1 and 2), is that the friction ring 33 is held form-locking andpositionally stabilized in the coupling body 32. For this, the frictionring 33 is provided with pegs 37 which extend axially end to end andengage form-locking in notches 36 arranged radially displaced from theinternal diameter of the coupling body 32. To form an inseparablejunction between the friction ring 33 provided with a friction area 38and the coupling body 32, pegs 37, for example, are stamped over on thenotches 36. As an alternative, or in addition, a welding of theseconstruction parts can be provided. The coupling body 32 is positionallystabilized on the rim 34 of the indexing gear 33 and experiences anaxial limit on the shoulder 35. The completed synchronizing unit 30assembled from the component parts is illustrated in FIG. 5.

FIG. 6 shows a further variant of the subassembly of the invention. Thesubassembly 40 includes two construction parts, the indexing gear 41 aswell as a transmission element 42, which assumes the function of thecoupling body as well as that of the friction ring. The transmissionelement 42, which has an L-shaped profile in longitudinal section and aconical friction area 48, is centered on the rim 44 of the indexing gear41 and experiences an axial limit on the shoulder 45.

FIG. 7 illustrates a subassembly 50a which is comprised of an indexinggear 51, a coupling body 52 and a friction ring 53. In accordance withFIG. 1, the coupling body 52 is centered here on the rim 54 and bracedon the shoulder 55 of the indexing gear 51. To produce a simplesynchronization, a synchronizing ring 56 is arranged on the frictionarea 58a of the friction ring 53.

FIG. 8 illustrates a subassembly 50b which corresponds to the structureof subassembly 50a represented in FIG. 7. To produce a twofoldsynchronization, synchronizing rings are arranged on both sides of thefriction ring 53. The synchronizing ring 56 encloses friction ring 53and stands in connection with this over friction area 58a. On theinside, synchronizing ring 57 is braced on friction area 58b.

FIG. 9 depicts a threefold synchronization in association with asubassembly 60a. The coupling body 62 is centered on the rim 64 of theindexing wheel 61 and braced on the shoulder 65. The friction ring 63 isheld form-locking in the coupling body 62 by pegs. The indexing gear 61is provided in one piece with an axially projecting inner cone 69 whichis arranged radially apart from the friction ring 63. In a compartmentradially bounded by the friction ring 63 and the inner cone 69, a firstsynchronizing ring 67 is installed which is arranged over friction areas68b and 68c on the friction ring 63 or on the inner cone 69. The secondsynchronizing ring 66 is guided outside the friction ring 63 on frictionarea 68a.

The subassembly 60b illustrated in FIG. 10 differs from subassembly 60ain FIG. 9 by a separately constructed inner cone 70. This is heldform-locking through axially projecting pegs 71 arranged peripherallydistributed in recesses 72 of the indexing gear.

It will be appreciated by those skilled in the art that changes can bemade to the embodiments described above without departing from the broadinventive concept. It is understood, therefore, that this invention isnot limited to the particular embodiments disclosed, but it is intendedto cover modifications within the spirit and scope of the presentinvention.

We claim:
 1. A synchronizing device having a two part subassembly (40) comprising an indexing gear (41) connected to a transmission element (42) having an L-shaped profile, the transmission element (42) including a coupling body portion and a friction ring, the indexing gear (41) being made of a high quality casting and the transmission element (42) being constructed as a high quality stamped metal part manufactured in a deep drawing process.
 2. The synchronizing device according to claim 1 wherein the coupling body portion has external gearing on an outside diameter and is centered with an interior diameter on a rim of the indexing gear.
 3. The synchronizing device according to claim 1 wherein the indexing gear (41) is made of a high quality casting GS
 45. 